Method for preventing overload in telecommunications networks with IMS by always-on for a call received by a user; - if the GGSN is going to deactivate said user PDP Context for having been inactive, the association [user IP, GGSN IP, SGSN IP] is not eliminated from an AAA server in which this association was previously saved, and furthermore the P-CSCF in which said user is located adds an indicator that said user is registered in IMS but without an active PDP context; and, when an incoming call is received: - the P-CSCF verifies the status of the user PDP Context by means of said indicator, and if it is not active, said PDP context is reactivated for which the P-CSCF informs the GGSN about the IP address which must be assigned to said user, and - if said IP ' address has not been assigned to another user, an attempt is made to reactivate the PDP Context using the address given by the P-CSCF for which - the GGSN uses the Network-Requested PDP context activation procedure, a consultation to the AAA server asing that IP address as the main consultation parameter being necessary; - the AAA server with that IP address as an index responds to the GGSN with the SGSN IP address under which the user is located; - and if said IP address has already been assigned, a restart is carried out after the failure of the call.